Pps/ police officers were shown 54 video clips showing 14 suspects from head to torso so that movement and expression were visible --> clips were baced up by evidence (so it was known if suspects were lying or not) and lasted between 6-145 seconds.

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Interviewing suspects

Mann's study - Detecting Lies

Procedure (continued...)

Police officers first filled out a questionnare about their experience detecting lies/liars.

They then watched the clips - after each clip they had to indicate whether they thought the suspect was lying or telling the truth, & then rate how confident they were about their decision.

Pps were also ased to write down any cues they'd used to detect the liars.

Results:

Mean lie accuracy - 66.2%

Mean truth accuracy -63.6%

This was not significantly different but both significantly greater than chance.

Experience in interviewing did correlate with truth accuracy.

Most frequently used cues - gaze/eye contact and movements

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Interviewing suspects

Mann's study - Detecting Lies

Evaluation points:

Reliability: A standardised procedure was used - so more easily replicated (high reliability mean more 'sound' conclusions can be made).

Validity: High ecological validity - interviews with suspects took place in real police interview settings. Police would normally record and watch back interviews. High mundane realism.

Participant variables: Some police officers may be better at detecting lies than others or developing rapport with suspects.

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Interviewing suspects

Inbau - Interrogation techniques

Inbau believes that it is justifiable for the police to lie, decieve or use tricks during a interview/interrogation with suspects in order to force a confession.

Inbau's '9 steps' to interrogation:

Direct confrontation

Give chance to shift blame

Never allow suspect to deny guilt

Ignore excuses

Reinforce sincerity to ensure suspect is receptive

If suspect cries, infer guilt

Pose an 'alternate question' - one more socially acceptable but both infers guilt.

Try to get suspect to admit guilt in front of witnesses

Document suspects admission.

Remember - interrogations are designed to increase arousal and anxiety in order for suspects to give a confession.

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Interviewing suspects

Inbau - Interrogation techniques

Evaluation points:

Reliability:

Yes - Inbau outlines 9 steps which can be followed/replicated/used as standardised procedure.

No - Inbau's 9 steps would most likely be carried out differently by different police officers/police stations in different areas/countries, therefore steps cannot be replicated to see if results/interrogation of suspects is consistant.

Validity: Lacks external validity, ie. is ethnocentric as these steps are only used in USA.

Ethics: Possible 'psychological harm' - suspects are interviewed for long periods of time, bombarded with questions, told directly they're thought to be guilty, and any attemps to explain innocence is ignored --> this may then lead to a false confession.

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Interviewing suspects

Gudjohnsson's study - False confessions

Aim: To document the case of 17yr old 'FC's' false confession, who at the time was distressed and susceptible to interrogative pressures.

Methodology - Case study

Subject/ Pp: 17 yr old 'FC, who was accused of two murders. He was of averae intelligence, suffered from no mental illness and his personality was not obviously abnormal.

Background:

In 1987, two elderly women were found battered to death in their home.

The women's savings were missing and there was evidence of sexual assult.

FC was arrested a few days later because of some inconsistancies in his account of his movements during an earlier routine enquiry and e was spending more money than usual.

There was no forensic eveidence to link him to the crime.

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Interviewing suspects

Gudjohnsson's study - False Confessions (continued...)

The police interviews:

After his arrest, FC was denied access to a solicitor

His first interview lasted nearly 14hrs with breaks

To start with FC denied being at the scene, but after being repeatedly accused of lying he agreed.

Many leading questions were used that were accusatory and many suggested that he was sexually impotent, which he found distressing. Eventually he confessed.

The next day he retracted his statement in front of a duty solicitor. There were 3 further interviews.

After a year in jail, he was released by a court after another person pleaded guilty to the crimes - This was a case of 'coerced compliant' false confession.

Psychiatric examination: In prison he was examined by psychiatrists and no evidence of mental illness was found. However, he did score a 10 on Gudjohnsson's Suggestibility Scale making him abnormal in that respect.